nodegit: Fix return type of Repository#createBlobFromBuffer

types/nodegit/nodegit-tests.ts

@@ -62,3 +62,5 @@ const signature = Git.Signature.now("name", "email");
 signature.name();
 signature.email();
 signature.when();
+
+repo.createBlobFromBuffer(Buffer.from("test")).then((oid: Git.Oid) => oid.cpy());

types/nodegit/repository.d.ts

@@ -153,7 +153,7 @@ export class Repository {
     /**
      * Create a blob from a buffer
      */
-    createBlobFromBuffer(buffer: Buffer): Oid;
+    createBlobFromBuffer(buffer: Buffer): Promise<Oid>;
     treeBuilder(tree: Tree): Promise<Treebuilder>;
     /**
      * Gets the default signature for the default user and now timestamp